1. Field of the Invention
The present invention pertains to patient interface systems, and, in particular, to a patient interface device structured to deliver a flow of breathing gas to a patient that includes a mechanism for providing multi-axis access to the patient's face as needed.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver positive airway pressure (PAP) therapy to treat certain medical disorders, the most notable of which is obstructive sleep apnea (OSA). Known PAP therapies include continuous positive airway pressure (CPAP), wherein a constant positive pressure is provided to the airway of the patient in order to splint open the patient's airway, and variable airway pressure, wherein the pressure provided to the airway of the patient is varied with the patient's respiratory cycle. Such therapies are typically provided to the patient at night while the patient is sleeping.
Non-invasive ventilation and pressure support therapies as just described involve the placement of a patient interface device including a mask component having a soft, flexible cushion on the face of a patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal cushion having nasal prongs that are received within the patient's nares, a nasal/oral mask that covers the nose and mouth, or a full face mask that covers the patient's face. Such patient interface devices may also employ other patient contacting components, such as forehead supports, cheek pads and chin pads. The patient interface device is connected to a gas delivery tube or conduit and interfaces the ventilator or pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head.
Non-invasive ventilation interface devices are typically worn by patients for several days. This extended period of treatment necessitates periodic, temporary access to the mouth and nose by the caregiver for things such as eating, drinking, speaking, and/or medication. One option for gaining such access is to remove the interface device. While effective, this solution causes all sizing settings to be completely lost in the process, necessitate a re-sizing when the interface device is to be put back into place on the patient. Another option is provided by the interface device described in United States Patent Application Publication No. 2011/0023883 (“the '883 application:”), which maintains sizing by providing a hinge between the mask and headgear for oro-nasal access. In particular, the interface device described in the '883 application includes a mask system that allows the mask to lift up-and-away from the wearer's face without the need to remove the headgear. However, the mask can only be lifted away from the face on a single-axis hinge in a single plane that is perpendicular to the wearer's face. This is a problem as the mask's orientation remains fixed in all but the plane of movement. Therefore, the elbow connector and attached circuit (i.e., delivery conduit) takes-up space and limits the range of motion and ability to “lock” the mask into place. Furthermore, the weight of the mask creates notable torque on the hinge, further complicating any workable “locking” solution. Thus, in that system, the mask must be manually held in the up-and-away position.